Third-Order Hydrodynamic Loads on an Oscillating Vertical Cylinder in Water

1999 ◽  
Vol 121 (1) ◽  
pp. 16-21 ◽  
Author(s):  
M. Markiewicz ◽  
P. Łe¸tkowski ◽  
O. Mahrenholtz
Keyword(s):  
Harmonic Component ◽  
Vertical Cylinder ◽  
Offshore Structures ◽  
Third Order ◽  
Earthquake Excitation ◽  
Hydrodynamic Loads ◽  
Third Harmonic ◽  
The Third ◽  
Steep Waves ◽  
Order Components

The third-harmonic component of the third-order hydrodynamic loads on a vertical circular cylinder oscillating in water is calculated by a conventional perturbation method within the framework of a potential theory. Although the third-order forces are expressed in terms of the first, second, and third-order components of the velocity potential, the latter is not directly required for the calculation. It is replaced by a properly defined linearized radiation potential via Haskind-like theorem. The results of the study are applicable to the analysis of high-frequency resonances of deepwater offshore structures under earthquake excitation or under steep waves (ringing problem).

scholarly journals Ultrafast Third-Order Nonlinear Optical Response Excited by fs Laser Pulses at 1550 nm in GaN Crystals

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3194
Author(s):  
Adrian Petris ◽  
Petronela Gheorghe ◽  
Tudor Braniste ◽  
Ion Tiginyanu
Keyword(s):  
Harmonic Generation ◽  
Nonlinear Optical ◽  
Laser Pulses ◽  
Third Harmonic Generation ◽  
High Repetition Rate ◽  
Third Order ◽  
Third Harmonic ◽  
The Third ◽  
High Repetition ◽  
Gan Crystal

The ultrafast third-order optical nonlinearity of c-plane GaN crystal, excited by ultrashort (fs) high-repetition-rate laser pulses at 1550 nm, wavelength important for optical communications, is investigated for the first time by optical third-harmonic generation in non-phase-matching conditions. As the thermo-optic effect that can arise in the sample by cumulative thermal effects induced by high-repetition-rate laser pulses cannot be responsible for the third-harmonic generation, the ultrafast nonlinear optical effect of solely electronic origin is the only one involved in this process. The third-order nonlinear optical susceptibility of GaN crystal responsible for the third-harmonic generation process, an important indicative parameter for the potential use of this material in ultrafast photonic functionalities, is determined.

Imaging Cracks in Bones Using Acoustic Nonlinearity: A Simulation Study

2011 ◽  
Vol 97 (5) ◽  
pp. 728-733
Author(s):  
Yang Liu ◽  
Xiasheng Guo ◽  
Zhao Da ◽  
Dong Zhang ◽  
Xiufen Gong
Keyword(s):  
Time Reversal ◽  
Three Dimensional ◽  
Harmonic Component ◽  
Ultrasonic Signal ◽  
Long Bone ◽  
Third Harmonic ◽  
Acoustic Nonlinearity ◽  
The Third ◽  
Nonlinear Approach ◽  
Radial Depth

This article proposes an acoustic nonlinear approach combined with the time reversal technique to image cracks in long bones. In this method, the scattered ultrasound generated from the crack is recorded, and the third harmonic nonlinear component of the ultrasonic signal is used to reconstruct an image of the crack by the time reversal process. Numerical simulations are performed to examine the validity of this approach. The fatigue long bone is modeled as a hollow cylinder with a crack of 1, 0.1, and 0.225 mm in axial, radial and circumferential directions respectively. A broadband 500 kHz ultrasonic signal is used as the exciting signal, and the extended three-dimensional Preisach-Mayergoyz model is used to describe the nonclassical nonlinear dynamics of the crack. Time reversal is carried out by using the filtered third harmonic component. The localization capability depends on the radial depth of the crack.

Analysis of error motions of axial locking-prevention hydrostatic spindle

2018 ◽  
Vol 233 (1) ◽  
pp. 3-17
Author(s):  
Penghai Zhang ◽  
Yaolong Chen
Keyword(s):  
Significant Influence ◽  
Harmonic Component ◽  
Necessary Condition ◽  
Third Harmonic ◽  
The Third ◽  
Fourth Harmonic ◽  
Radial Error ◽  
Tilt Error ◽  
Error Motion ◽  
Error Averaging

Hydrostatic spindles are widely used in precision optical grinder and lathe. Their high precision comes from the error averaging effect of oil film. The purpose of this paper is to give the quantitative analysis of the error averaging effect for a newly developed axial locking-prevention hydrostatic spindle. An approximate error motion model of the hydrostatic spindle is established to analyze the internal relationship between the geometric errors of the shaft and the error motions of the spindle including radial, tilt and axial error motions. The theoretical analysis shows that, the roundness errors of the two journals have a major impact on error motions while the coaxiality errors of two journals, the perpendicularity errors of front thrust plate and the coaxiality errors of the land of back thrust bearing, have no significant influences on error motions. The elliptical component of roundness errors of the two journals has significant influence on the axial error motion but no influence on the pure radial and tilt error motions, resulting into the fourth harmonic component of axial error motion. The trilobal component of roundness errors of the two journals has significant influence on the pure radial and tilt error motions but no influence on the axial error motion, resulting in the third harmonic component of pure radial and tilt error motions. The changes of recess pressures are not necessary condition for the error motions. Additionally, the experiment analysis shows that, the third harmonic component is the main part of the measured radial error motion and the third, fourth harmonic components are the main parts of the measured face error motion, which can be reasonably explained by the theory. The model proposed in this paper can be used to guide the precision design and optimization of hydrostatic spindle.

Third-order nonlinear optical properties of the Na2S–PbS–GeS2 sulfide glasses and the Na2S–PbO–GeS2 oxysulfide glasses

1999 ◽  
Vol 14 (2) ◽  
pp. 330-333 ◽  
Author(s):  
Zhong Hua Zhou ◽  
Hiroyuki Nasu ◽  
Tadanori Hashimoto ◽  
Kanichi Kamiya
Keyword(s):  
Optical Properties ◽  
Nonlinear Optical ◽  
Third Harmonic Generation ◽  
Optical Nonlinearity ◽  
Chemical Durability ◽  
Number Density ◽  
Third Order ◽  
Third Harmonic ◽  
The Third ◽  
Maximum Value

The third-order optical nonlinearity of glasses of the Na2S–PbS–GeS2 and Na2S–PbO–GeS2 systems was measured by third-harmonic generation method. The third-order nonlinearities of glasses of both systems increase with the increasing lead content. The maximum value of the third-order optical nonlinearity was 3.00 × 10-12 esu. The addition of PbO basically has little influence on third-order optical nonlinearity, and the largest nonlinearity is 1.49 × 10-12 esu. The minimum appearing at 15 mol% PbO can be explained by the decrease of number density of lead and sulfur. Chemical durability of oxysulfide glasses is superior to that of a pure sulfide system; thus the addition of PbO is important in this sense.

Identification of Coulomb Friction in Robot Drives and Other Mechanical Systems Through Observation of Third Harmonic Generation

1994 ◽  
Vol 208 (5) ◽  
pp. 329-336 ◽  
Author(s):  
D J Brookfield
Keyword(s):  
Coulomb Friction ◽  
Robot Control ◽  
Control Strategies ◽  
Harmonic Component ◽  
Experimental Tests ◽  
Third Harmonic ◽  
The Third ◽  
Drive Systems ◽  
Driving Torque ◽  
Frictional Behaviour

One of the main difficulties in introducing improved robot control strategies is a lack of knowledge of the frictional behaviour of robot drive systems. The aim of the present paper is to describe a technique for the identification of Coulomb friction based on the response of the robot drive to a sinusoidal driving torque The presence of a third harmonic component in the resulting velocity is a consequence of the Coulomb non-linearity and it is shown theoretically, through computer simulation and in experimental tests, that the coefficient of Coulomb friction can be estimated from the amplitude of the third harmonic component. The identification method is shown to be applicable to any mechanical system that can be subjected to a sinusoidal forcing torque or force.

scholarly journals On kinematics of very steep waves

2013 ◽  
Vol 13 (8) ◽  
pp. 2101-2107 ◽  
Author(s):  
L. Shemer
Keyword(s):  
Wave Breaking ◽  
Wide Spectrum ◽  
Wave Train ◽  
Vertical Acceleration ◽  
Wave Group ◽  
Third Order ◽  
Large Wave ◽  
The Third ◽  
Steep Waves ◽  
Group Velocities

Abstract. Experiments on extremely steep deterministic waves generated in a large wave tank by focusing of a broad-banded wave train serve as a motivation for the theoretical analysis of the conditions leading to wave breaking. Particular attention is given to the crest of the steepest wave where both the horizontal velocity and the vertical acceleration attain their maxima. Analysis is carried out up to the third order in wave steepness. The apparent, Eulerian and Lagrangian accelerations are computed for wave parameters observed in experiments. It is demonstrated that for a wave group with a wide spectrum, the crest propagation velocity differs significantly from both the phase and the group velocities of the peak wave. Conclusions are drawn regarding the applicability of various criteria for wave breaking.

Wave Kinematics and Pressure Field of Third-Order Theory for Bichromatic Bi-Directional Waves in Water of Finite Depth

2014 ◽  
Vol 580-583 ◽  
pp. 2166-2169
Author(s):  
Hu Huang ◽  
Guo Liang Li
Keyword(s):  
Pressure Field ◽  
State Of The Art ◽  
Finite Depth ◽  
Order Theory ◽  
Offshore Structures ◽  
Structural Members ◽  
Third Order ◽  
Wave Kinematics ◽  
The Third ◽  
Directional Waves

Based on the third-order theory for bichromatic bi-directional waves in water of finite depth, a set of explicit formulas for the state-of-the art quantities of wave kinematics for horizontal and vertical particle displacements, velocities and accelerations, and wave pressure field is developed, and would be much more accurate and realistic in the design of harbor, coastal and offshore structures and their structural members.

scholarly journals Selected Organometallic Compounds for Third Order Nonlinear Optical Application

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 254 ◽  
Author(s):  
Anna Popczyk ◽  
Aouatif Aamoum ◽  
Anna Migalska-Zalas ◽  
Przemyslaw Płóciennik ◽  
Anna Zawadzka ◽  
...  
Keyword(s):  
Physical Vapor Deposition ◽  
Incident Beam ◽  
Organometallic Compounds ◽  
Basis Set ◽  
Nonlinear Susceptibility ◽  
Third Order ◽  
Linear Absorption ◽  
Third Harmonic ◽  
The Third ◽  
Linear Optical Properties

In this paper, we present the third harmonic generation response of Znq2 (Bis-(8-hydroxyquinolinato)zinc), Cuq2 (8-Hydroxyquinoline copper(II)), and Alq3 (Tris-(8-hydroxyquinoline)aluminum) organometallic compounds. An experiment was conducted for s and p polarizations of incident beam, using the Maker fringes technique. The third order nonlinear susceptibility χ(3) was estimated using the Kubodera and Kobayashi comparative model, on the grounds that presented compounds exhibit high linear absorption of the generated third harmonic wavelength (355 nm). These complexes were deposited as thin films using the physical vapor deposition (PVD) method. Investigated complexes vary in terms of the coordination center and number of quinoline ligands, which visibly influence their nonlinear response. The global hybrid B3LYP functional with the basis set 6-31G(d) was used in computing the linear and non-linear optical properties. The computed γtot value (8765.36 × 10−36 esu for Cuq2) is superior to that of methylene blue (γ = 32.00 × 10−36 esu). The calculated theoretical values were found to be in good agreement with the experimental results.

On the Occurrence of Strong Higher Harmonic Wave Forces and Induced Ringing Loads on Vertical Cylinders

2002 ◽  
Author(s):  
John Grue ◽  
Morten Huseby
Keyword(s):  
Harmonic Wave ◽  
Vertical Cylinder ◽  
Offshore Structures ◽  
Load Cycle ◽  
Wave Forces ◽  
Wave Elevation ◽  
Secondary Load ◽  
Steep Waves ◽  
Acceleration Of Gravity ◽  
Vertical Cylinders

Experimental observations of a secondary load cycle in the force acting on a vertical cylinder exposed to long and steep waves are discussed. A complementary discussion of the occurrence of ringing of models of offshore structures is given. The height of the secondary load cycle is typically up to about 0.1–0.15 times the peak to peak force on the cylinder. The load cycle is observed for a nondimensional wavenumber kR in the range 0.1–0.33 and for a Froude number Fr = ωζm/gD exceeding about 0.4. Pronounced ringing occurs for the same parameter range. (k the wavenumber, R the cylinder radius, ω the wave frequency, ζm the maximal wave elevation, g the acceleration of gravity, D = 2R.)

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